The accuracy of a varian 600CD LINAC and the Pinnacle³ (v6.2b) treatment planning system with regard to IMRT implementation.

Abstract

With IMRT now the future for the accurate delivery of radiation therapy, an investigation into the beam delivery system and the radiotherapy planning system has been undertaken to determine the accuracy and limitations of both systems. Results outlined in the following investigation have shown limitations in the beam delivery system as a result of the individual leaf construction and the Linac mechanics. Results from this investigation have shown limitations applied to IMRT fluence conversion and machine delivery process must include a minimum 2cm equivalent segment size with the smallest possible secondary collimator setting encompassing all segments, 400 MU/min dose rate and 4MU/segment to provide optimum IMRT delivery employing the Pinnacle³ planning system and the varian 600CD LINAC. Appying these limitations was also shown to minimize the effects due to the leaf construction.